Sn0.1-Li4Ti5O12/C as a promising cathode material with a large capacity and high rate performance for Mg–Li hybrid batteries

The development prospects of conventional Li-ion batteries are limited by the paucity of Li resources. Mg-Li hybrid batteries (MLIBs) combine the advantages of Li-ion batteries and magnesium batteries. Li⁺ can migrate rapidly in the cathode materials, and the Mg anode has the advantage of being dendrite-free. In this study, a type of Li₄Ti₅O₁₂ composite material doped with Sn⁴⁺ and a conductive carbon skeleton (Li₄Ti_4.9Sn_0.1O₁₂/C, Sn_0.1-LTO/C) was prepared by a simple one-pot sol-gel method. The doped Sn⁴⁺ replaces part of Ti⁴⁺ in the crystal lattice, which makes Ti³⁺ require charge compensation, thus improving the ionic conductivity. The intervention of the conductive carbon skeleton further improves the conductivity of the Sn_0.1-LTO/C composite material. The performance of Sn_0.1-LTO/C as the cathode of MLIBs is explored. The initial discharge capacity was 159.1 mA h g^-1 at 0.5 C, and it was maintained at 105 mA h g^-1 even after 500 cycles. The excellent electrochemical performance is attributed to a small amount of Sn doping and the involvement of the conductive carbon skeleton, which indicated that the Sn_0.1-LTO/C composite material provides great potential application in MLIBs.